The present invention relates to a machine for harvesting fruits, berries and the like, from fruit trees and bushes planted in rows, of the type including a straddling chassis or frame capable of moving across a field, a shaker assembly mounted on the chassis and including at least one pair of elongate shaker members which have active parts extending in a first direction, broadly speaking in the longitudinal direction of the machine, and which are spaced transversely from each other and situated on respective opposite sides of the longitudinal median axis of the machine, each shaker member consisting of a flexible material rod, and a drive mechanism connected to the rods to drive them synchronously with a reciprocating motion in a second direction perpendicular to the first direction and defining therewith an oscillation plane for each rod.
The invention relates in particular, although not exclusively, to harvesting grapes and it will be more particularly described in connection with this type of harvest. However, the machine of the present invention is equally capable of being used for harvesting other fruits and berries, for example blackcurrants, gooseberries, raspberries, or coffee beans and olives.
Most conventional grape-picking machines use practically the same principle for harvesting grapes. The principle consists in beating or shaking the vines by imparting sinusoidal or pseudo-sinusoidal motion thereto with an amplitude and at a frequency suitable for detaching the grapes or the bunches of grapes. This motion is transmitted to the vine via shaker or beater members disposed in such a manner as to act either on the vinestock or stem or else on the vegetation, i.e. on the fruit-bearing portion of the vine, depending on the type and number of shaker or beater members used.
The shaker or beater members usually have active parts which broadly extend in a horizontal direction (first direction) in the longitudinal direction of the machine and said sinusoidal to-and-fro motion is effected in a horizontal direction (second direction) perpendicular to the first direction. However, for some types of fruit-bearing bushes, it can be judicious, in a known manner, to dispose the shaker members so that their active parts are inclined to the horizontal at a greater or lesser angle, as appropriate, and/or so that their sinusoidal to-and-fro motion is effected in a second direction that can also be inclined to the horizontal at a greater or lesser angle.
The percentage of bunches and/or individual grapes which are detached from the vine depends on the number and the amplitude of the oscillations to which a given bunch of grapes is subjected. The more energetic the shaking to which a given bunch of grapes is subjected, and the more frequently it is shaken, the more likely said bunch is or its individual grapes are to become detached from the vine.
The number and the amplitude of the oscillations to which a given bunch of grapes is subjected themselves depend on various parameters that can be chosen, in particular the amplitude and the frequency of the drive mechanism associated with the shaker members, the length of the active area of said shaker members, the stiffness or the flexibility thereof, and the speed at which the machine advances, together with other factors which are imposed by the vine itself, in particular the way it is trained, its shape and its resistance to the motion of the beater members.
However, while detaching bunches of grapes or individual grapes, the shaker members may damage the vine, which may be detrimental to the health of the vine and to the crop itself It is therefore generally necessary to find a compromise between the various parameters mentioned above in order to obtain an acceptable percentage of harvested grapes or bunches of grapes without giving rise to unacceptable damage to the vine. For more details of the prior art in this regard, see patent FR-A-2.605.487, which is hereby incorporated herein by way of reference.
In most prior art harvesting machines, the shaker members, if they are designed to act on the vegetation of the vine, consist of circular cross-section rods which are flexible to a greater or lesser degree. The rods are made either from a single material, such as glassfiber-reinforced resin, polyamide, spring steel, etc., or of two materials.
In the latter case (FR-A-2.159.250 and FR-A-2.313.859) each rod is made of fiberglass and its active portion intended to come into contact with the vegetation of the vine is provided with a metal tube or sleeve intended to avoid wear or cracking of the fiberglass rod because of rubbing and/or repeated impacts of said rod on the vegetation and/or on the stakes supporting the vine. The presence of the metal tube or sleeve increases the weight of the active region of the shaker rod and modifies how it bends under static and dynamic conditions. In particular, for a given frequency of oscillation, the amplitude of the oscillatory movement and the speed of the active part of the rod are increased, especially in the case of rods with a free rear end, and this can aggravate the damage caused to the vine.
Although a compromise may be found between the various parameters mentioned above to obtain an acceptable percentage of grapes or bunches of grapes or other berries harvested without causing excessive damage to the vine or other fruit-bearing bushes carrying the berries to be harvested, with shaker members consisting of circular cross-section rods it is difficult to prevent unwanted vertical movement of the rods in use, i.e. in a third direction perpendicular to the first and second directions mentioned above, in addition to their horizontal (second direction) oscillatory movement, which is the only one which is beneficial in terms of shaking the fruit-bearing bushes and thus of harvesting the fruit. The disadvantage of these unwanted vertical movements is that they detach leaves which are mixed with the harvested fruit and therefore complicate cleaning of the crop.
Also, the side of the shaker rods in contact with the vegetation of the fruit-bearing bushes to be shaken is worn by abrasion in use. As a result the flexibility of each rod in a horizontal oscillation plane, i.e. in the plane defined by the first and second directions mentioned above, increases as the rod wears away, making shaking less effective. This is because, as the rod becomes more flexible, it becomes less capable of entraining with it, during its oscillatory motion, the vegetation of the fruit-bearing bush to be shaken. Consequently, the rod must be replaced with a new rod after a period in service or following a degree of wear.
The principal aim of the present invention is therefore to provide a harvesting machine of the type defined in the preamble whose shaker members in the form of flexible rods, are in use less subject to unwanted movement in the third direction.
A subsidiary object of the present invention is to provide a harvesting machine of the type defined above in which the shaker members also have an increased service life.
According to one aspect of the present invention, there is provided a machine for harvesting fruits, berries and the like, from fruit trees and bushes planted in rows, said machine including a straddling chassis capable of moving across a field, a shaker assembly mounted on the chassis and including at least one pair of elongate shaker members which have active parts extending in a first direction, generally in the longitudinal direction of the machine, and which are spaced transversely from each other and situated on respective opposite sides of the longitudinal median axis of the machine, each shaker member consisting of a flexible material rod, which has a required flexibility characteristic, and a drive mechanism connected to the rods to drive them synchronously with a reciprocating motion in a second direction generally perpendicular to the first direction and defining therewith an oscillation plane for each rod, characterized in that each rod of said at least one pair of shaker members has an elongate base part which has said required flexibility characteristic for the rod in its plane of oscillation and which has an oblong cross-section which is larger in a third direction, perpendicular to said plane of oscillation, than in said second direction, said cross-section having two main geometrical axes respectively oriented in the second and third directions and dimensions such that its moment of area (Ix) about the main axis oriented in the second direction is significantly greater than its moment of area (Iy) about the main axis oriented in the third direction.
To this end, the rod may have an elongate base part which has said required flexibility characteristic for the rod in its plane of oscillation and which has an oblong cross-section which is larger in a third direction, perpendicular to said plane of oscillation, than in said second direction, said cross-section having two main geometrical axes respectively oriented in the second and third directions and dimensions such that its moment of area (=second moment of inertia) about the main axis oriented in the second direction is significantly greater than its moment of area about the main axis oriented in the third direction and its dimension in said third direction is less than a predefined value.
In practice, the first and second directions mentioned above are usually horizontal or substantially horizontal and the third direction is then vertical or substantially vertical (however, as already mentioned above, the first and second directions may sometimes be inclined to the horizontal).
Under the above conditions, each rod is clearly more rigid in the vertical direction (third direction) than in the horizontal direction (second direction). Each rod is therefore less likely to be subject to unwanted vertical movement and if there is any such movement its amplitude is significantly reduced compared to that of a circular cross-section rod. Furthermore, by keeping the vertical dimension of the cross-section of said base part or that of each rod less than a predefined value, which is in turn at most equal to, and preferably less than, the diameter of prior art circular cross-section rods, each rod offers up to the vine or other fruit-bearing bush to be shaken a contact surface area the same as or smaller than that of prior art circular cross-section rods. This prevents the rod having an enlarged contact surface area, because of the oblong shape of the cross-section of said base part, which could burst the grapes or other berries on impact with the shaker rods. Moreover, the wear of each rod by abrasion can influence its horizontal stiffness, unless measures specified hereinafter are applied, but has virtually no effect on the vertical stiffness of the rod. Consequently, prolonged use of rods in accordance with the invention does not increase the risk of damage caused to the vines by unwanted vertical movements.
The machine in accordance with the invention can also have one or more of the following features:
a) the moment of area about the main axis oriented in the second direction is at least twice the moment of area about the main axis oriented in the third direction;
b) said predefined value is not greater than 32 mm and preferably equal to 30 mm for a rod having one end attached to a support which can pivot about a fixed point of said chassis and whose opposite end is attached to a point that can move in a direction substantially parallel to the longitudinal median axis of the machine;
c) said oblong cross-section is elliptical in shape with a major axis in the third direction and a minor axis in the second direction;
d) said oblong cross-section has a rectangular shape with a longer side in the third direction and a shorter side in the second direction;
e) said major axis or said longer side has a length from 25 mm to 28 mm and said minor axis or said shorter side has a length from 15 mm to 18 mm;
f) said base part of each rod forms a core for the rod concerned and each rod also has a wear part which covers said core and is made from a material and has a thickness such that said rod has flexibility characteristics in the second and third directions that are practically unchanged relative to those of said core, even after substantial wear of said wear part;
g) said wear part has a circular cross-section whose center is coincident with that of said core;
h) said wear part has a thickness which is greater on the side of the rod facing toward the longitudinal median axis of the machine than on the opposite side of said rod;
i) said wear part has a cross-section which, on the side of the rod facing toward the longitudinal median plane, is substantially the shape of a half-ellipse whose minor axis is colinear with the major axis of the elliptical cross-section of said core and, on the opposite side of said rod, the shape of a half-ellipse whose major axis is colinear with said major axis of said elliptical cross-section of said core, with a substantially constant thickness on the latter side;
j) said wear part has a cross-section whose dimensions in the third and second directions respectively measured along two main geometrical axes of the cross-section of said core are from 22 mm to 30 mm;
k) said core has an elliptical or rectangular cross-section whose larger dimension, in the third direction, is from 19 mm to 23 mm and whose smaller dimension, in the second direction, is from 10 mm to 15 mm;
l) the base part or core of each rod is made from a material chosen from the group including glassfiber-reinforced resin, aramide (Kevlar(copyright)) fibers or carbon fibers, and spring steel;
m) said core is a double core made up of two parallel metal strips spaced from each other in the second direction and which have their width oriented in the third direction; the two strips of the double core are preferably made of spring steel; each of the two strips is preferably from 14 to 18 mm wide and from 1 to 3 mm thick and their spacing is preferably from 6 to 12 mm; under these conditions the wear part preferably has a circular cross-section with a diameter from 23 to 30 mm;
n) the wear part of each rod is made of a material chosen from the group including polyamides, polyurethanes and polyethylenes;
o) said core is a different color to the wear part.
According to a further aspect of the invention, there is provided a shaker rod having one or more of the features defined above with regard to the rods of the harvesting machine indicated above.